[PATCH] D118054: [AArch64][SVE] Mark PFALSE as side-effect free.

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen created this revision.
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This helps MachineCSE remove redundant PFALSE instructions.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118054

Files:
  llvm/lib/Target/AArch64/SVEInstrFormats.td
  llvm/test/CodeGen/AArch64/sve-pfalse-machine-cse.mir


Index: llvm/test/CodeGen/AArch64/sve-pfalse-machine-cse.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/sve-pfalse-machine-cse.mir
@@ -0,0 +1,26 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -run-pass=machine-cse -mtriple=aarch64 -mattr=+sve -o - %s | FileCheck %s
+---
+name:            pfalse
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $p0
+
+    ; CHECK-LABEL: name: pfalse
+    ; CHECK: liveins: $p0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:ppr = COPY $p0
+    ; CHECK-NEXT: [[PFALSE:%[0-9]+]]:ppr = PFALSE
+    ; CHECK-NEXT: [[UZP1_PPP_B:%[0-9]+]]:ppr = UZP1_PPP_B [[COPY]], [[PFALSE]]
+    ; CHECK-NEXT: [[UZP1_PPP_B1:%[0-9]+]]:ppr = UZP1_PPP_B killed [[UZP1_PPP_B]], [[PFALSE]]
+    ; CHECK-NEXT: $p0 = COPY [[UZP1_PPP_B1]]
+    ; CHECK-NEXT: RET_ReallyLR implicit $p0
+    %0:ppr = COPY $p0
+    %2:ppr = PFALSE
+    %3:ppr = UZP1_PPP_B %0, %2
+    %4:ppr = PFALSE
+    %5:ppr = UZP1_PPP_B killed %3, %4
+    $p0 = COPY %5
+    RET_ReallyLR implicit $p0
+...
Index: llvm/lib/Target/AArch64/SVEInstrFormats.td
===================================================================
--- llvm/lib/Target/AArch64/SVEInstrFormats.td
+++ llvm/lib/Target/AArch64/SVEInstrFormats.td
@@ -606,6 +606,7 @@
   let Inst{8-4}   = 0b00000;
   let Inst{3-0}   = Pd;
 
+  let hasSideEffects = 0;
   let isReMaterializable = 1;
 }
 


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